著者

小栗 朋子

出版者

新領域創成科学研究科環境システム学専攻

巻号頁・発行日

2013-09-27

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学位の種別: 課程博士

著者

小栗 朋子 石橋 由梨 吉永 淳

出版者

一般社団法人 日本環境化学会

雑誌

環境化学 (ISSN:09172408)

巻号頁・発行日

vol.23, no.1, pp.43-47, 2013 (Released:2013-09-25)

参考文献数

26

被引用文献数

2 3

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Total and inorganic arsenic (tAs and iAs) analysis of soils and house dust samples, collected pair-wise from 41 residences of general public in Japan, was carried out to estimate contributions of these non-dietary oral sources to total daily exposure level of iAs, an established human carcinogen. Total As concentration in the samples was determined after mixed acid digestion followed by ICP mass spectrometric (ICPMS) determination. Non-spectroscopic interference arising from residual carbon in the digest was successfully compensated by addition of 3% acetic acid to sample digest and standard solution. Concentration of iAs in soil and house dust samples (n=20 each) was measured by liquid chromatography- ICPMS after extraction with synthetic gastric juice. Median tAs concentration in soil (n=38) and house dust (n=40) was 10 and 2.5 mg/kg, respectively. Median iAs (AsIII+AsV) concentration was <0.01 and 0.24 mg/kg, respectively. Assuming that adult unintentionally ingest 50 mg each of soil and house dust, daily exposure level was estimated to be 0.0005 and 0.012 μg/day, respectively. When recently reported daily dietary iAs intake (mean of two estimates: 15.4 μg/day) is considered, contributions from soil and house dust to total daily oral exposure was estimated to be 0.003 and 0.08%, respectively. Soil and house dust ingestion, as well as inhalation exposure (estimated to be 0.02 μg/day), was found to be insignificant for total daily iAs exposure of Japanese.

著者

小栗 朋子 吉永 淳

出版者

日本衛生学会

雑誌

日本衛生学雑誌 (ISSN:00215082)

巻号頁・発行日

vol.69, no.3, pp.177-186, 2014

被引用文献数

8

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Objective: The objective was to estimate the inorganic arsenic (iAs) intake of the general Japanese adult population by a probabilistic approach. Methods: Bioaccessible iAs concentrations in rice (n=56) and hijiki (n=32), the two food items that are the major iAs sources for the Japanese, were measured by liquid chromatography-ICP mass spectrometry. The concentration in cooked rice was estimated from the measured concentration in a raw rice sample while taking into consideration the loss of iAs during cooking. The iAs concentration in hijiki was measured using soaked hijiki samples. The daily consumption of cooked rice and soaked hijiki was taken from published data. The distribution profile of daily iAs intake was estimated by multiplying the bioaccesible iAs concentration in cooked rice and soaked hijiki samples by the amount of these samples consumed daily, which were randomly extracted according to the respective distributions. This process was repeated 10,000 times. Results: The distribution profiles of iAs concentration in rice and hijiki were normal and log-normal, respectively, and those of the amount of cooked rice and soaked hijiki consumed were beta and log-normal, respectively. The daily bioaccessible iAs intake values were estimated to be 19 and 59 μg/day at 50 and 95 percentile. At 50 percentile iAs intake, the contributions from rice and hijiki were estimated to be equal, whereas the contribution from hijiki increased with the estimated total daily iAs intake. Conclusions: The iAs intakes of Japanese subjects estimated in previous duplicated portion studies were fairly consistent with the present estimation. Moreover, it was confirmed that the cancer risk derived from dietary iAs intake of the general Japanese population was not negligible.

著者

中山 祥嗣 磯部 友彦 岩井 美幸 小林 弥生 小栗 朋子 竹内 文乃

出版者

一般社団法人日本衛生学会

雑誌

日本衛生学雑誌 (ISSN:00215082)

巻号頁・発行日

vol.73, no.2, pp.156-163, 2018 (Released:2018-05-31)

参考文献数

37

被引用文献数

1 1

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In this review, we present an initial plan for exposure assessment in the Japan Environment and Children’s Study (JECS) by focusing on a biomonitoring technique and discuss the challenges encountered when using the biomonitoring technique for exposure measurements. JECS registered 103,099 pregnant mothers and has been following children born to them. Various biological samples were collected from mothers during pregnancy (blood and urine), at birth (blood and hair) and at check-up one month after birth (breast milk). Samples were also collected from children at birth (cord blood) and at check-up one month after birth (hair and blood spot). Those samples will be used to assess maternal and foetal exposures to chemical substances. Measurement reliability, i.e., intraclass correlation coefficient (ICC), and attenuation bias related to low ICCs should be taken into consideration when using the biomonitoring results. Along with the biomonitoring technique, simulation models, pharmacokinetic (PK) models and exposomics techniques are under development in JECS. New analytical techniques include deciduous teeth measurements and -omics analyses. In particular, PK models and sensor technologies are one of the most important methodologies for future JECS exposure analyses. Statistical methods for examining the effects of intercorrelated multiple exposures as well as nondetection data should also be explored.

著者

小栗 朋子 片岡 修治 鈴木 剛 吉永 淳

出版者

一般社団法人 日本環境化学会

雑誌

環境化学 (ISSN:09172408)

巻号頁・発行日

vol.27, no.1, pp.9-15, 2016-12-15 (Released:2017-09-27)

参考文献数

33

被引用文献数

1

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Lead is a neurotoxin and it has a significant adverse effect on the neurobehavioral development of children due to a low-level exposure. In order to see if lead-containing household products are present in the indoor environment in Japan, various products (n=250) were analyzed for total lead concentration with an X-ray fluorescence spectrometry. Lead was detected in 18 of 250 samples at the concentration 0.019 to 14%. It was found that lead was contained in paints and polyvinyl chloride (PVC) covering of the products. Two samples with painted surface had concentrations of lead exceeding 0.06% in the paint, the regulatory limit set by the Japan Paint Manufacturers Association. Eight samples with PVC covering (e.g. extension cord, supply cable) had more lead concentrations than the tolerable maximum concentration value of the RoHS directive in 2006 (0.1%). These products were produced outside Japan, or produced before execution of the RoHS directive. Bioaccessibility of lead in the products was relatively low, ranging from 0.43 to 4.6%. Daily bioaccessible lead intake of a child via the ingestion of fragments of such products was estimated to range from 0.21 to 90 µg/day, and total daily bioaccessible lead intake including contributions from other media (e.g. diet and soil) was estimated to be 4.7 to 94 µg/day. Blood lead concentration of a child, who ingests this amount of bioaccessible lead, was estimated to be 0.75 to 15 µg/dL based on a model formula of the EPA. The result suggested that products with extremely high lead concentration can pose health risk to children via the ingestion of house dust contaminated with fragments of surface covering of such products.

著者

小栗 朋子

出版者

東京大学 新領域創成科学研究科 環境学研究系 環境システム学専攻

巻号頁・発行日

2010-09-27

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報告番号: ; 学位授与日: 2010-09-27 ; 学位の種別: 修士 ; 学位の種類: 修士(環境学) ; 学位記番号: 修創域第3620号 ; 研究科・専攻: 新領域創成科学研究科環境システム学専攻

著者

小栗 朋子 吉永 淳

出版者

日本衛生学会

雑誌

日本衛生学雑誌 (ISSN:00215082)

巻号頁・発行日

vol.69, no.3, pp.177-186, 2014 (Released:2014-09-24)

参考文献数

33

被引用文献数

8

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Objective: The objective was to estimate the inorganic arsenic (iAs) intake of the general Japanese adult population by a probabilistic approach. Methods: Bioaccessible iAs concentrations in rice (n=56) and hijiki (n=32), the two food items that are the major iAs sources for the Japanese, were measured by liquid chromatography-ICP mass spectrometry. The concentration in cooked rice was estimated from the measured concentration in a raw rice sample while taking into consideration the loss of iAs during cooking. The iAs concentration in hijiki was measured using soaked hijiki samples. The daily consumption of cooked rice and soaked hijiki was taken from published data. The distribution profile of daily iAs intake was estimated by multiplying the bioaccesible iAs concentration in cooked rice and soaked hijiki samples by the amount of these samples consumed daily, which were randomly extracted according to the respective distributions. This process was repeated 10,000 times. Results: The distribution profiles of iAs concentration in rice and hijiki were normal and log-normal, respectively, and those of the amount of cooked rice and soaked hijiki consumed were beta and log-normal, respectively. The daily bioaccessible iAs intake values were estimated to be 19 and 59 μg/day at 50 and 95 percentile. At 50 percentile iAs intake, the contributions from rice and hijiki were estimated to be equal, whereas the contribution from hijiki increased with the estimated total daily iAs intake. Conclusions: The iAs intakes of Japanese subjects estimated in previous duplicated portion studies were fairly consistent with the present estimation. Moreover, it was confirmed that the cancer risk derived from dietary iAs intake of the general Japanese population was not negligible.